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Cucumber fungus #874571

Asked June 25, 2024, 7:55 AM EDT

What to do about a fungus that has spread from cucumber seedlings and plants and then spread to all of my summer squash, winter squash, and pumpkin plants? This is an old garden space, where I rotate crops and was never attacked before. I pulled & got rid of all the plants. I am not sure what type of fungus or mold, the other vegetable plants seem fine so far. I wonder what organic process to treat this area of the garden? And can I plant cucurbits again? (The attached pic has a dusting of baking soda and vinegar spray so the fungus was not downy mildew. I’m thinking maybe acthranose or angular leaf rot?)

Orange County Vermont

Expert Response

Hello Ruth,

Thank you for reaching out to the Extension Master Gardener helpline with your question. Do you happen to have any leaves left that you can mail so our team can take a closer look? If so, here is a link to our specimen form with mailing instructions:

https://www.uvm.edu/sites/default/files/Extension-Community-Horticulture/PDC_Specimen_Worksheet_fillable_form.pdf

Also, do you see any webbing or mites on the undersides of the leaves? You may need a hand lens to determine this. A closer look at the actual leaves can help determine if is due to spider mites.

If you can mail in leaves or provide additional images of the undersides that would help us be more certain what is causing this. If these aren't an option you could check out the below links on spider mites to see if any resonate with what you were seeing:

https://extension.umd.edu/resource/spider-mites-vegetables/

https://hortsense.cahnrs.wsu.edu/fact-sheet/cucumber-pumpkin-squash-spider-mites/

https://ag.umass.edu/vegetable/fact-sheets/two-spotted-spider-mite

https://extension.umn.edu/yard-and-garden-insects/spider-mites

Angular leaf spot and Anthracnose are great thoughts. We would expect to see more individual spotting first for Angular. You may also be seeing some burn from the vinegar spray. Again, it's hard to be certain without the specimen, but if that is not an option please check out the links with spider mite information.

Thank you,

Replied June 27, 2024, 9:10 PM EDT

Hi Extension experts,

Thanks for your answer, still think I have a fungus of some sort. It has now spread to Brussels sprouts. I’m in fear for the rest of the garden…stone wall separates this area from tomatoes, beans, root veggies. But I am overwhelmed by this. I want to send samples but this holiday week…will anyone be there on Friday if I send tomorrow? Should I just hang on til Monday? Sorry, but I have tried diy remedies to no avail and prefer to not employ the heavy fungicides. Need more info and help to address it.

Gardened in Vermont all my life and never had this problem!

Thanks, Ruth

Sent from my iPhone

On Jun 27, 2024, at 9:10 PM, Ask Extension <<personal data hidden>> wrote:

The Question Asker Replied July 02, 2024, 6:08 PM EDT

Good Morning Ruth,

I'm sorry to hear this! You can send in the sample and our team can put it in the frig until our plant pathologist can look at it. Can you confirm if you are spraying everything with vinegar?

Thank you!

Replied July 03, 2024, 9:48 AM EDT

I am no longer spraying the plants in case it was making them worse and weve had lots of rain. So the ones I am sending you have not been sprayed.

I am off to bag, label, and mail!

Thanks for your help!!

Sent from my iPhone

On Jul 3, 2024, at 9:48 AM, Ask Extension <<personal data hidden>> wrote:

The Question Asker Replied July 03, 2024, 10:06 AM EDT

Thanks Ruth! It would help if you could fill out this form for the Plant Diagnostic Lab: https://www.uvm.edu/sites/default/files/Extension-Community-Horticulture/PDC_Specimen_Worksheet_fillable_form.pdf and send along with your sample.

Please note that UVM is closed tomorrow for the July 4 holiday and again over the weekend as normal. We don't want your specimen to decompose before we have a chance to look at it so I wanted to give you a heads up about our hours.

Happy Gardening! Replied July 03, 2024, 1:44 PM EDT

Hi Expert friends,

I sent samples w/your form via express mail so you should get it on Friday. Hopefully you can still examine them next week. I disposed of most of the plants as it was spreading but left a few in the garden so I can send samples again.

Thanks for your help! Ruth

Sent from my iPhone

On Jul 3, 2024, at 1:44 PM, Ask Extension <<personal data hidden>> wrote:

The Question Asker Replied July 03, 2024, 2:58 PM EDT

Thanks Ruth -- we will keep an eye out for it!

Happy Gardening! Replied July 03, 2024, 3:01 PM EDT

I have received your specimens, and have put them in storage so the Plant Pathologist can take a look at them when she returns to the clinic next Tuesday. Thank you.

An Ask Extension Expert Replied July 05, 2024, 12:39 PM EDT

Cucumber fungus #874571

Expert Response

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